I have been having a problem with my redundant PostgreSQL setup over the last couple of weeks. I run two Postgres servers with a WAL Logging Warm Standby system using pg_standby from 8.3. When the master server is under heavy load and generating a lot of WAL traffic the secondary server has been tripping and going active.

After checking all the logs and putting pg_standby in debug mode there was still no clue as to why this was happening.

Monitoring & analysing your PostgreSQL server logs with PgFouine provides you with a way to see which queries are performing badly and need optimisation. It can also provide insight into busy periods and give some basic query stats such as the number of INSERT, DELETE, UPDATE, and SELECT operations.